About 42,000 residents have been displaced or are in active evacuations with an additional 45,000 in "be prepared to evacuate" status as the Hawk Fire threatened northern Reno, local officials said late on Sunday morning.
Local TV footage showed flames approaching roads. In eyewitness video verified by Reuters, smoke from the hills billowed over nearby residential neighbourhoods.
Fire-tracking websites showed evacuation zones extending from the Sierra Nevada hills to the University of Nevada in northwest Reno.
The fire has burned 5261 hectares so far, officials said at a press conference on Sunday. The fire was human-caused and remains under investigation, they said.
Three civilians and three first responders have been injured, said Shane Akerson, a commander leading fire and rescue operations.
Richard Edwards, chief of Truckee Meadows Fire Protection District said firefighters worked amid "extreme red flag conditions".
Red flag conditions are a combination of warm temperatures, very low humidity and strong winds that raise the risk of wildfires.
"We expect those same strong conditions to come back this afternoon," Edwards said on Sunday.
Nevada Governor Joe Lombardo declared a state of emergency late Saturday in Washoe County, which includes Reno and parts of Lake Tahoe.
"This is an active and rapidly evolving situation, and I urge everyone in the affected areas to remain vigilant and follow the direction of local officials," Lombardo said in a statement.
Lombardo authorised the deployment of two National Guard helicopters to help fight fires and 60 National Guard personnel to support operations with the Washoe County Sheriff's Office, officials said.
The Reno-Tahoe International Airport remained outside the evacuation area, and commercial flights were operating normally on Sunday.
